Department Of Physics

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Author: search.filters.author.Fortunelli, Alessandro

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    Adsorption and activation of CO2 on a Au19Pt subnanometer cluster in aqueous environment
    (Elsevier B.V., 2022-04-15T00:00:00) Mondal, Krishnakanta; Megha; Banerjee, Arup; Fortunelli, Alessandro
    We employ ab initio density functional theory based method to investigate the ability of a subnanometer bimetallic Au19Pt cluster to adsorb and activate a CO2 molecule in an aqueous electrochemical environment. We find that, in water, Au19Pt gets negatively charged at zero bias and selectively promotes the adsorption and activation of the CO2 molecule via electron transfer and through the hybridization of oxygen p-orbitals and partially filled platinum d-orbitals. Notably, Pt acts as a collector of negative charge and behaves as a CO2-activating single-atom catalyst embedded within a robust Au20-like framework, thus suggesting Au19Pt as a potential candidate for CO2 mitigation. � 2022 Elsevier B.V.
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    Ab Initio Modeling of the ZnO-Cu(111) Interface
    (American Chemical Society, 2021-12-31T00:00:00) Mondal, Krishnakanta; Megha; Banerjee, Arup; Fortunelli, Alessandro; Walter, Michael; Moseler, Michael
    The morphology at the catalytically active interfacial site of ZnO/Cu in the commercial ZnO/Cu/Al2O3 catalyst for CO2 hydrogenation to methanol is still an open question. In the present study, we employ ab initio density functional theory based methods to gain insight into the structure of the ZnO-Cu interface by investigating the morphology of supported ZnO nano-ribbons at the interface with the Cu(111) surface in the presence of hydrogen and water molecules. We find that the stabilities of free-standing ZnO nano-ribbons get enhanced when they are supported on the Cu(111) surface. These supported nano-ribbons are further stabilized by the adsorption of hydrogen atoms on the top of O atoms of the nano-ribbons. Interestingly, the hydrogenated nano-ribbons are found to be equally stable and they appear to be an array of independent chains of ZnOH motifs, suggesting that the hydrogenated nano-ribbons are structurally fluxional. The edge of these fluxional nano-ribbons is stabilized via a triangular reconstruction with a basic composition of Zn6O7H7 in the presence of water molecules. Such a triangular structure gets further stabilized when it is attached to a bulk-like part of the ZnO/Cu(111) system. Furthermore, we find that the triangular reconstruction is energetically favorable even at the methanol synthesis conditions. Therefore, we propose that, under methanol synthesis conditions, the motif Zn6O7H7 represents a stable form at the interface between the bulk-like part of ZnO and the Cu(111) surface in the ZnO/Cu/Al2O3 based commercial catalyst. � 2021 American Chemical Society